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5-HTTLPR polymorphism impacts human cingulate-amygdala interactions: a genetic susceptibility mechanism for
Lukas Pezawas1, Andreas Meyer-Lindenberg, Emily M Drabant
1Genes, Cognition and Psychosis Program, National Institute of Mental Health, National Institutes of Health, 10 Center Drive 4S235, Bethesda, Maryland 20892-1379, USA.
Nature Neuroscience
|May 10, 2005
Summary
Individuals with the short allele of the serotonin transporter gene show altered brain structure and function in emotion-processing regions. This genetic variation is linked to increased anxiety and a higher risk of depression.
Area of Science:
- Neuroscience
- Genetics
- Psychiatry
Background:
- The short allele of the serotonin transporter gene is associated with increased anxiety, amygdala reactivity, and depression risk.
- Understanding the neural mechanisms linking this genotype to emotional traits is crucial.
Purpose of the Study:
- To investigate the neuroanatomical and functional brain differences in healthy individuals carrying the short allele of the serotonin transporter gene.
- To elucidate the neural mechanisms underlying the association between this gene polymorphism and emotional regulation.
Main Methods:
- Multimodal neuroimaging techniques were employed in a large sample of healthy human subjects.
- Morphometrical analyses assessed gray matter volume in limbic regions.
- Functional neuroimaging examined amygdala-cingulate circuit activity during fearful stimulus processing.
Main Results:
- Short-allele carriers exhibited reduced gray matter volume in the perigenual cingulate and amygdala.
- A functional feedback circuit between the amygdala and cingulate cortex showed reduced coupling in short-allele carriers.
- The degree of circuit coupling inversely correlated with temperamental anxiety, explaining nearly 30% of its variation.
Conclusions:
- Genotype-related alterations in the anatomy and function of the amygdala-cingulate circuit are implicated in emotion regulation.
- These findings suggest a developmental, systems-level mechanism contributing to normal emotional reactivity and genetic susceptibility to depression.